According to this article, "one out of every two U.S. schools has a teacher tracking that kind of data with one extremely popular app, ClassDojo." According to their blog, they have a user base of "millions more in over 100 countries." The application encourages and rewards specific behaviours in class (see the introduction) such as teamwork, participation, working hard, participating and persistence. Penalties are applied for things like disrespect, talking out of turn, being unprepared or being off-task. The marketing is viral, with one teacher recommending it to others. There have been criticisms of the service, notably from the NY Times, over privacy concerns, to which the company hasresponded. New Tech City reports, "Sam Chaudhary, co-founder of ClassDojo, tells us flatly 'we are not a data company.' He explains how he plans to grow a tech company without harnessing user data." Via Alexander Russo.